ROTARY PISTON ENGINE

Abstract

A rotary piston engine comprising at least one rotary piston for compressing and/or expanding a working gas in at least one working chamber and a method for compressing and/or expanding a working gas in a rotary piston engine are provided. The rotary piston engine comprises at least one rotary piston with at least one rotatably mounted rotational body and at least one sealing portion that can be moved relative to the rotational body for sealing the at least one working chamber. In the method for compressing and/or expanding a working gas in a rotary piston engine, the working gas is compressed by a rotary piston in a first working chamber and transferred into a second working chamber in order to be ignited, wherein the working gas is supplied with fuel in the second working chamber and/or is further compressed.

Description

The invention relates to a rotary piston engine comprising at least one rotary piston for compressing and/or expanding a working gas in at least one working chamber and to a method for compressing and/or expanding a working gas in a rotary piston engine.

A similar rotary piston engine and a method for compressing and/or expanding a working gas in a rotary piston engine is known e.g. from DE 10 2011 109 966.

Such a rotary piston engine for compressing and expanding a working gas comprises at least one working piston about the rotational axle of which generally several working chambers are formed and rotatable in which the working gas is compressed, optionally ignited and expanded after ignition, where the working chambers can be arranged in succession in the axial direction and/or in the circumferential direction of the working piston. In addition, such a rotary piston engine generally comprises at least one auxiliary piston with a geometry that is complementary to the working piston and rolls in a sealing manner along the working piston so that at least one working chamber of variable volume is formed for compressing and expanding the working gas.

Unlike a reciprocating engine of traditional design, all work cycles (aspiration, compression, ignition, expansion) of the rotary piston engine are performed during rotation of the rotary piston, without the rotary piston changing its direction of motion. Different working cycles can there also occur simultaneously in different working chambers. The explosion energy of the ignited working gas preferably acts directly in the circumferential direction on the working piston which is also responsible for compressing the working gas. Like in an aircraft gas turbine, the explosion energy of the ignited working gas is thereby used directly to drive the compressor and to compress the working gas, so that in theory, a particularly high degree of efficiency of the rotary piston engine arises.

However, known problems of rotary piston engines are compression pressure losses due to relatively long gas courses and sealing problems of the working chambers in the compression and expansion stage, thermal expansion of the housing and the rotary pistons, in particular due to the large friction surfaces and high rotational speeds, the centrifugal forces and the inertia of the working gas having adverse effects on the flow of gas and the mixing of the air-fuel mixture prior to ignition, the oil inlet into the working chambers in the operating or resting state, controllability of the ignition due to rapidly rotating pistons in particular at different rotational speeds (change of load). This reduces the output and efficiency of the rotary piston engine. For these reasons, the rotary piston engine has in practice not been able to prevail despite the many advantages over reciprocating piston engines.

The invention is therefore based on the object to improve a known rotary piston engine of the aforementioned type and a method for its operation such that improved output and increased efficiency is achieved. Flexibility in the executability and the adaptability to the most varied situations and expectations is of significance, in particular to meet the requirements of a wide variety of applications. In the focus of development are, inter alia, the use of different fuels (gasoline, diesel, hydrogen, etc), for externally-supplied ignition and spontaneous ignition, controllability and adjustability at least in the same manner as for the reciprocating engine (gas intake, ignition timing, gas outlet, gas quantity, volumes, ignition chamber, etc.), usability as a synchronous engine e.g. for generators, block heating plant and machine tools, but as well for driving vehicles, vessels or aircrafts. The configuration is to be as simple as possible.

The object of the invention is satisfied by individual solutions (aspects) that already by themselves, but in particular in their interaction enable a rotary piston engine and a method for its operation with improved output and increased efficiency, where the individual solutions are claimed individually as well as in combination.

According to a first aspect of the invention, the object is satisfied by the rotary piston engine according to claim 1 for compressing and/or expanding a working gas in at least one working chamber, comprising at least one rotary piston with at least one rotatably mounted rotational body and at least one sealing portion which can be moved relative to the rotational body for sealing the at least one working chamber. Due to the sealing portion being movable relative to the rotational body, sealing gaps between the stationary and the rotating parts of the rotary piston engine, for example, due to thermal expansion of materials, can in every operating mode of the rotary piston engine be better closed and sealed, so that the pressure and fuel losses in the compression and expansion stage are reduced and the output and the efficiency of the rotary piston engine are improved.

For better understanding of the invention described and claimed, some terms are clarified in advance:

The terms axial, radial and circumferential direction respectively pertain to the rotational axle of the rotary piston respectively at issue. Axial direction refers to a direction along or parallel to the rotational axle of the respective rotary piston. Radial direction, however, refers to a direction perpendicular to said rotational axle. The circumferential direction extends along the circumference of an arbitrary circle whose center is located on the rotational axle.

The first aspect of the invention, as mentioned earlier, relates mainly to sealing the working chambers between the stationary and the rotating parts of the rotary piston engine. The term sealing surface in the context of this invention refers to the surface of a stationary or rotating part of the rotary piston engine that in a sealing manner faces a corresponding surface of a stationary or rotating part of the rotary piston engine—the so-called sealing partner—to prevent leakage of the working gas through the sealing gap between the sealing surfaces. In the present case, there are seals between stationary and rotating parts of the rotary piston engine (working pistons or auxiliary pistons against the housing) as well as seals among rotating parts of the rotary piston engine relative to each other (working pistons against auxiliary pistons).

It can be advantageous to have the at least one rotary piston fulfills at least one of the following requirements:

• • The rotary piston is rotatable about a rotational axle while maintaining the seal of the at least one working chamber.
  • At least one rotary piston is a working piston for compressing and/or expanding a working gas, about the rotational axle of which the at least one working chamber is formed and/or rotates, whereby preferably at least two working chambers are disposed in succession in the axial direction and/or in the circumferential direction of the working piston.
  • At least one rotary piston is an auxiliary piston having a geometry that is complementary to the working piston to roll in a sealing manner against the working piston, preferably to form a working chamber with a variable volume.

It can also prove useful, however, to have the at least one rotational body fulfill at least one of the following requirements:

• • The rotational body comprises at least one sealing surface at least temporarily sealing the at least one working chamber during the rotating motion, wherein the sealing surface preferably in the axial direction and/or in the radial direction and/or in the circumferential direction faces away from the rotational body.
  • The rotational body comprises at least one recess for forming the at least one working chamber.
  • The rotational body comprises an adjustable geometry such that the volume of at least one recess is variable for forming the at least one working chamber.
  • The rotational body comprises at least two recesses for forming a respective working chamber, where the recesses are preferably arranged in succession in the axial direction and/or in the circumferential direction, where the recesses are of different dimensions preferably in the axial direction and/or in the radial direction and/or in the circumferential direction.
  • The rotational body comprises at least one cavity sealed against the at least one working chamber.

It can also prove practical, however, the have the at least one sealing portion fulfill at least one of the following requirements:

• • The sealing portion comprises at least one sealing surface which preferably in the axial direction and/or in the radial direction and/or the circumferential direction faces away from the sealing portion, where the sealing surface is formed preferably as a rotationally symmetrical surface or as a portion thereof, where the sealing surface preferably has the shape of a cylinder jacket and/or a cone jacket and/or a sphere jacket or of a circular disk or at least a portion thereof.
  • The sealing portion at a sealing surface comprises at least one preferably line-shaped sealing lip which projects in the direction of a sealing partner, where the sealing lip preferably extends in a wave-shaped or sinusoidal manner in the circumferential direction, where the wave-shaped or sinusoidal sealing lip travels a phase angle of at least 180° around the circumference of the rotary piston.
  • The sealing portion is at least in sections disposed at an axial and/or a radial end of the rotational body, where the sealing portion preferably encompasses the rotational body preferably in the axial direction and extends at least in sections along both axial ends of the rotational body.
  • The sealing portion is reversibly transferable between a first state, in which a sealing surface of the sealing portion connects flush to or at a distance from a sealing surface of the rotational body and/or to a sealing surface of another sealing portion, and in a second state, in which the sealing surface of the sealing portion in the direction of a sealing partner projects beyond the sealing surface of the rotational body and/or beyond the sealing surface of another sealing portion.
  • The sealing portion is movable relative to the rotational body along a line in a plane including the rotational axle of the rotary piston, preferably along or parallel to the rotational axle of the rotary piston and/or radially and/or at an acute angle to the rotational axle of the rotary piston.
  • The sealing portion is movable only along a preferably straight line relative to the rotational body, whereas all the other motions of the sealing portion relative to the rotational body are blocked.
  • The sealing portion is movable relative to at least one further sealing portion and/or to the rotational body while maintaining the seal of the at least one working chamber.
  • The sealing portion is slidably guided at the rotational body.
  • The sealing portion seals the at least one working chamber in the axial direction and/or in the radial direction and/or in the circumferential direction.
  • The sealing portion is resiliently preloaded or preloadable against the rotational body, where the resilient preload preferably pushes apart or presses together the sealing portion and the rotational body.
  • The sealing portion is configured such that it is during rotation of the rotary piston movable due to the centrifugal force, where the sealing portion is preferably due to the centrifugal force spaced from the rotational axle of the rotary piston.
  • The sealing portion at least at one end, in the direction of rotation of the rotary piston preferably at a front end, comprises a bevel to facilitate penetration of the sealing portion into a complementary geometry of a sealing partner.
  • The sealing portion is substantially a rotationally symmetrical component or a portion thereof, where the sealing portion is formed preferably circular-segment-shaped, ring-segment-shaped or arc-shaped.
  • The sealing portion forms an outer edge of the rotary piston.
  • The sealing portion is in the axial direction and/or in the radial direction and/or in the circumferential direction fixed at the rotational body in a form-fit manner.
  • The sealing portion is made of heat-resistant material, preferably ceramics.
  • The sealing portion is made of ductile material, preferably copper.
  • The sealing portion is made of porous material.
  • The sealing portion is made of material having the same thermal expansion coefficient as the housing and/or at least one further rotary piston.
  • At least two sealing portions are in the axial direction and/or in the radial direction and/or in the circumferential direction disposed adjacent and/or in overlap.
  • At least two sealing portions together form a continuous or enclosed or self-contained seal.
  • At least two sealing portions are movable relative to each other while maintaining a continuous or closed or self-contained seal.
  • At least two sealing portions are identical or symmetrical or complementary to each other.
  • At least two sealing portions seal the at least one working chamber completely in the axial direction and/or in the radial direction and/or in the circumferential direction.
  • At least two sealing portions are arranged in pairs at opposite axial ends of the rotational body.
  • At least two sealing portions are resiliently preloaded or preloadable against each other, where the resilient preload preferably pushes apart or presses together the sealing portions.

An improved seal of the working chamber can in every operating state of the rotary piston be ensured by a sealing portion configured according to at least one of the above features, where the sealing portion can be particularly well adapted to the characteristics of the respective sealing partner in terms of materials and contours.

It can also be useful to have the rotary piston engine comprise a housing fulfilling at least one of the following requirements:

• • The housing comprises at least one inlet for introducing working gas into the working chamber.
  • The housing comprises at least one outlet for discharging working gas from the working chamber.
  • The housing is at least in part constructed in a mirror-symmetrical manner, preferably mirror-symmetrical to a plane which is spanned by the rotational axles of two rotary pistons.
  • The housing comprises at least two parts, preferably at least two substantially mirror-symmetrical parts, preferably at least two identical parts so as to cover the rotary piston on different sides of its circumference.
  • The housing is split substantially in a plane which is spanned by the rotational axles of two rotary pistons or in a plane parallel thereto.

A housing according to the foregoing features is easy to manufacture, compact and easy to assemble and can also again be dismantled in the case of required access to the rotating components of the rotary piston engine.

According to a second aspect of the invention, the above-formulated object is satisfied by the rotary piston engine according to claim 6, preferably in combination with at least one of the foregoing embodiments for compressing and/or expanding a working gas in at least one working chamber, having a housing and having at least one rotary piston rotatably mounted in the housing, where the housing comprises at least one lubricant channel for supplying lubricant to the rotary piston and/or for removing lubricant from the rotary piston. Force-feed circulatory lubrication via the lubricant channels can in any operating state of the rotary piston engine ensure a better seal of the working chamber.

In an advantageous embodiment of the invention, the lubricant channel fulfills at least one of the following requirements:

• • The lubricant channel removes lubricant from the rotary piston into a lubricant reservoir.
  • The lubricant channel is configured such that lubricant collects in the lubricant reservoir.
  • The lubricant channel extends at least in sections preferably in an arc-shaped manner around the rotary piston and/or around the working chamber.
  • The lubricant channel is constructed such that the lubricant adheres to the lubricant channel wall due to adhesion.
  • The lubricant channel is constructed such that the lubricant drains due to weight force.
  • The lubricant channel at least in sections extends within and/or outside the housing.
  • The lubricant channel at an apex above the rotary piston has a smaller radius of curvature than the greatest radius of the rotary piston, where the lubricant channel below the apex preferably has a larger radius of curvature than the greatest radius of the rotary piston.
  • The lubricant channel comprises at least one branching.
  • The lubricant channel comprises at least one lubricant supply line for supplying lubricant to the rotary piston, preferably at least to one mounting location of the rotary piston and/or to at least one sealing surface of the rotary piston.
  • The lubricant channel is part of a lubricant circuit, preferably of a closed lubricant circuit, where the lubricant removed from the rotary piston is preferably cleaned and is again supplied to the rotary piston.

The lubricant channel according to the above features can well distribute the required lubricant over the contact surfaces to be lubricated and reliably drain excess lubricant.

According to a further advantageous embodiment of the invention, the lubricant channel comprises at least one collecting portion for collecting lubricant from the rotary piston, where the collecting portion fulfils at least one the following requirements:

• • The collecting portion opens towards the rotary piston, preferably towards at least one mounting point of the rotary piston and/or towards at least one sealing surface of the rotary piston.
  • The collecting portion extends at least in sections in the circumferential direction of the rotary piston.
  • The collecting portion is disposed radially outside and axially within the rotary piston, or radially within and axially outside the rotary piston.
  • The collecting portion is configured such that it receives lubricant cast off from the rotary piston due to the centrifugal force.
  • The collecting portion comprises at least two parallel grooves which are separated from each other by at least one wall portion, where the wall portion—when viewed in cross-section—tapers or widens preferably from a proximal to a distal end and/or where the wall portion—when viewed in cross-section—is concave between the proximal end and the distal end, where the wall portion—when viewed in cross-section—preferably at the distal end comprises an arrow-shaped profile, the tip of which faces away from the proximal end of the wall portion.
  • The collecting portion comprises at least two parallel grooves which are preferably deeper than wide.
  • The collecting portion comprises a backflow inhibitor which prevents leakage of the lubricant already collected.
  • The collecting portion is configured to receive lubricant supplied to the rotary piston by force-feed circulatory lubrication in the operating state and in the resting state of the rotary piston engine.

According to a third aspect of the invention, the object formulated above is also satisfied by a method for compressing and/or expanding a working gas in a rotary piston engine, preferably in a rotary piston engine according to at least one of the preceding embodiments, where the working gas is compressed by a rotary piston in a first working chamber and transferred into a second working chamber in order to be ignited, characterized in that the working gas is in the second working chamber supplied with fuel and/or is further compressed.

It can be advantageous to have the method comprise at least one of the following steps:

• • The compressed working gas is passed through the rotary piston and/or through the housing of the rotary piston engine, preferably radially inwardly from the first working chamber into the second working chamber.
  • Fuel is injected into the second working chamber prior to and/or during and/or after the further compression.
  • The working gas is in the second working chamber further compressed by at least one reciprocating piston, where the reciprocating piston is preferably driven pneumatically and/or hydraulically and/or mechanically by a cam or eccentric shaft coupled to the rotary piston motion, where the reciprocating piston and the rotary piston particularly preferably run at the same rotational speed.
  • The working gas is introduced already in a compressed state into the first working chamber, where the compression is effected preferably by a turbocharger.
  • The working gas is in the second working chamber made to ignite by being supplied with fuel and/or by further compression.
  • The ignited working gas is passed through the rotary piston and/or through the housing of the rotary piston engine, preferably radially outwardly from the second working chamber into the first working chamber.

The preferred embodiments of the invention are described in detail below with reference to the figures.

BRIEF DESCRIPTION OF THE FIGURES

In the drawing:

FIG. 1 shows schematic views of a rotary piston engine according to the invention; in particular FIG. 1a shows a perspective view of a rotary piston engine according to the invention with a housing partially open which is split in a plane including the rotational axles of the rotary pistons; FIG. 1b shows a schematic sectional view of a rotary piston engine according to the invention for illustrating the interaction of the individual components; and FIG. 1c shows a schematic sectional view of a modification of the rotary piston engine according to the invention of FIG. 1b in which the rotary pistons in the left half of the image rotate in a phase that is shifted or opposite to the rotary pistons on the right half of the image to compensate an imbalance caused by the piston position, where four different work strokes (aspiration, compression, ignition/expansion and discharge) occur simultaneously in different working chambers of the rotary piston engine.

FIG. 2 shows schematic views of the rotary piston of a rotary piston engine according to the invention; in particular FIG. 2a shows a side view of the rotary pistons; FIG. 2b shows the rotary pistons with sealing portions in a front view in a first state in which the sealing surfaces of the sealing portions and of the rotational body at the auxiliary pistons extend flush with each other; and FIG. 2c shows the upper auxiliary piston with sealing portions in enlarged detail view and in a front view in a second state in which the sealing surfaces of the sealing portions project at the auxiliary pistons in the axial direction beyond the sealing surfaces of the rotational body.

FIG. 3 shows schematic views of a rotary piston of the rotary piston engine according to the invention being configured as a working piston; in particular FIG. 3a shows the rotary piston with sealing portions in side view in a first state in which sealing surfaces of the sealing portion and the rotational body extend flush with each other; FIG. 3b shows the rotary piston with sealing portions in a side view in a second state in which the sealing surfaces of the sealing portions project beyond the sealing surfaces of the rotational body in the radial direction.

FIG. 4 shows schematic views of a rotary piston of the rotary piston engine of the invention being configured as a working piston according to an advantageous variant; in particular FIG. 4a shows the working piston with sealing portions in a side view and an enlarged side view of a detail; FIG. 4b shows the working piston with sealing portions in a front view in a first state in which sealing surfaces of the sealing portion and the rotational body extend flush with each other; FIG. 4c shows the rotary piston with sealing portions in a front and an enlarged front view of a detail in a second state in which the sealing surfaces of the sealing portions project beyond the sealing surfaces of the rotational body in the radial direction; FIG. 4d shows a plan view of a rotary piston with sealing portions which extend in a wave-shaped manner in the circumferential direction.

FIG. 5 shows various schematic views of a rotary piston engine according to the invention in various work steps; in particular FIG. 5a shows a schematic sectional view of the rotary piston engine according to the invention for illustrating the work cycles in a reciprocating piston system or in the expansion stage, respectively (System A); FIG. 5b shows a schematic front view of the rotary piston engine according to the invention with an exposed rotary piston; FIG. 5c shows a schematic sectional view of the rotary piston engine according to the invention for illustrating the work cycles in a rotary piston system or in the compression stage, respectively (System B); and FIGS. 5d-f show simplified and reduced views based on FIGS. 5a-c.

FIG. 6 shows various schematic views of a rotary piston engine according to the invention in various work steps; in particular FIG. 6a shows a simplified schematic sectional view of the rotary piston engine according to the invention for illustrating the work cycles in a reciprocating piston system or in the expansion stage, respectively (System A); and FIG. 6b shows a schematic front view of the rotary piston engine from FIG. 6a for illustrating the work cycles in a rotary piston system or in the compression stage, respectively (System B);

FIG. 7 shows various views of a modification of the rotary piston engine according to the invention from FIG. 6; where FIGS. 7a and 7b are substantially based on FIG. 6a and FIG. 6b.

FIG. 8 shows schematic views of a rotary piston engine according to the invention with an internal reciprocating piston system for illustrating various drive concepts for the reciprocating piston; in particular FIG. 8a shows a reciprocating piston system with a pneumatic or hydraulic drive, where the reciprocating piston motion can be decoupled from the rotational motion of the working piston; FIG. 8b shows a reciprocating piston system with a crank drive and rod connection to the rotational axle of the working piston; and FIG. 8c shows a reciprocating piston system with a cam drive and two ignition chambers at the end sides.

FIG. 9 shows a schematic sectional view of a rotary piston engine according to the invention with an internal reciprocating piston system with a cam drive and an ignition chamber at the end side, where the reciprocating piston is driven mechanically by the axle of the working piston configured as a camshaft.

FIG. 10 shows schematic views for illustrating a first chronological series of steps of the method according to the invention for compressing and expanding a working gas in the rotary piston engine of the invention according to the eighth embodiment of the invention; in particular FIG. 10a shows the rotary piston when the gas outlet of the ignition chamber is closed, FIG. 10b shows the reciprocating piston during aspiration of the working gas of System B into the ignition chamber and the rotary piston during aspiration of air into the working chamber of System A; FIG. 10c shows the rotary piston when the gas inlet of the ignition chamber is closed and during aspiration of air into the working chamber of System A; and FIG. 10d shows the reciprocating piston during compression of the working gas in the ignition chamber of System B.

FIG. 11 show schematic views illustrating a second chronological series connecting to the first series of steps of the method for compressing and expanding a working gas in the rotary piston engine according to the invention; in particular FIG. 11a shows the reciprocating piston when blocking the gas inlet of the ignition chamber during simultaneous ignition by injection or externally-supplied ignition and the rotary piston when blocking the intake port of the working chamber of System A; FIG. 11b shows the rotary piston when opening the gas outlet of the ignition chamber for draining the working gas into the working chamber and the reciprocating piston during displacement of the residual gases from the ignition chamber and when blocking the gas backflow into the ignition chamber to avoid pressure on the piston top side and to relieve the reciprocating system (e.g. via the cam); FIG. 11c shows the rotary piston when the gas inlet of the ignition chamber is opened for shock flushing by precompressed air from System A due to the piston shape and during expansion of the working gas into and in the rotating working chamber for driving the working axle; and FIG. 11d shows the rotary piston 4 when the gas outlet is opened for discharging the combustion gases.

FIG. 12 shows schematic views for illustrating a third chronological series connecting to the second series of steps of the method for compressing and expanding a working gas in the rotary piston engine according to the invention; in particular FIG. 12a shows the rotary piston when the gas outlet of the ignition chamber is closed, when the combustion gases are discharged from the first working chamber and during aspiration of working air into the second working chamber; FIG. 12b shows the reciprocating piston during aspiration of the working gas into the ignition chamber; FIG. 12c shows the rotary piston when blocking the gas outlet of the first working chamber, when the chamber of the lower auxiliary piston is opened for discharging the residual gases into the housing and when the gas inlet of the ignition chamber is closed; and FIG. 12d shows the reciprocating piston during compression of the working gas.

FIG. 13 shows schematic views of a rotary piston engine of the invention according to an advantageous embodiment; in particular FIG. 13a shows a schematic perspective partial view of the rotary piston engine according to the invention with the housing partially open; FIG. 13b shows a schematic sectional view of the rotary piston engine of FIG. 13a according to the invention perpendicular to the rotational axles of the rotary pistons; FIG. 13c shows alternative configurations of collecting portions of a lubricant channel for collecting lubricant; FIG. 13d shows schematic views of the course of the lubricant channel and the collecting portion about one of the rotary pistons from which the lubricant is to be removed; FIG. 13e shows a schematic side view of a rotary piston formed as an auxiliary piston during rotation, where the lubricant cast off due to centrifugal force is shown schematically by droplets.

FIG. 14 shows schematic views of a rotary piston engine of the invention according to a further advantageous embodiment; in particular FIG. 14a shows a schematic sectional view of the rotary piston engine according to the invention perpendicular to the rotational axles of the rotary pistons in the intended installation position; and FIG. 14b shows the rotary piston engine of FIG. 14a in an inclined position in which the rotary piston engine is inclined relative to the intended installation position in an axis parallel to the rotational axles by an angle α/2.

FIG. 15 shows schematic views of a rotary piston engine of the invention according to a further advantageous embodiment of the invention; in particular FIG. 15a shows a schematic sectional view of a rotary piston engine according to the invention perpendicular to the rotational axles of the rotary pistons; and FIG. 15b shows a schematic sectional partial view of the rotary piston engine of FIG. 15a along the rotational axle of the upper auxiliary piston for illustrating the course of the lubricant channel.

FIG. 16 shows schematic views of a rotary piston engine of the invention according to yet a further advantageous embodiment of the invention; in particular FIG. 16a shows a schematic perspective partial view of a rotary piston engine according to the invention with a housing partially open; FIG. 16b shows a schematic sectional view of the rotary piston engine according to the invention perpendicular to the rotational axles of the rotary pistons; and FIG. 16c shows a sectional partial view of the rotary piston engine of FIG. 16b along the rotational axle of the upper auxiliary piston for illustrating the course of the lubricant channel.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the framework of the description, like reference numerals are used for the same features and, repetition of descriptions is dispensed with to the extent possible.

The rotary piston engine 1 shown in FIG. 1 operates according to the method principle described above for compressing and expanding a working gas and comprises a working piston 4 about its rotational axle 40 of which working chambers 2 are formed and can be rotated to compress the working gas, possibly to ignite it and expand it after ignition. Working chambers 2 are disposed spaced apart or in succession in the axial direction and in the circumferential direction of working piston 4. Working piston 4 comprises a rotational body 41 rotatably mounted in housing 5 having a plurality of movable sealing portions 42 for sealing working chambers 2 and with two recesses 43 for forming a respective working chamber 2 which are separated by slider 44. Each of the two auxiliary pistons 3 comprises two rotational bodies 31, 34 mounted jointly rotatably in housing 5 on which movable sealing portions 32, 33, 35, 36 are attached for sealing working chambers 2, where rotational bodies 31, 34 have a rolling geometry adapted to the rolling geometry of working piston 4 to perform a rolling motion in a manner sealing working piston 4 and housing 5.

The working gas is in a known manner introduced through an inlet (51; cf. FIGS. 8-12.) into working chambers 2 and compressed by rotation of working piston 4, possibly ignited and relaxed after ignition in working chambers 2. For being supplied with fuel and for ignition, the working gas can also be transferred through a channel (not shown) from the compression stage to the expansion stage. However, the working gas can also be ignited in one of the working chambers 2.

Housing 5 comprises a lubricant channel 6 for the supply and removal of lubricant S to or from upper auxiliary piston 3. This lubricant channel 6 comprises inter alia collecting portions 60 for collecting lubricant cast off from rotary pistons 3 due to centrifugal force. For force-feed circulatory lubrication of mounting points and axial sealing surfaces of rotary piston 3 with lubricant, several lubricant supply lines 65 (FIG. 1a) can run through housing 5. Further details on the lubricant course shall be described later in connection with FIGS. 13 to 16.

FIG. 2 shows schematic views of rotary pistons 3, 4 of rotary piston engine 1 of the invention and in particular illustrates the mode of operation of sealing portions 32, 33, 35, 36 and 42. As previously described in connection with FIG. 1, each of the two auxiliary pistons 3 of rotary piston engine 1 according to the invention comprises two rotational bodies 31, 34 mounted jointly rotatable in housing 5, where movable sealing portions 32, 33, 35, 36 are attached at each rotational body 31, 34 for sealing working chambers 2. With these sealing portions 32, 33, 35, 36, auxiliary piston 3 can maintain the seal of working chamber 2 also during rotation about its rotational axle 30 and during thermally induced material expansions.

Each rotational body 31, 34 also comprises a cavity 37 (FIG. 2a) sealed against working chamber 2 and sealing surfaces 31a/b/c, 34a/b/c in the axial direction, in the radial direction and in the circumferential direction facing away from rotational body 31, 34, 41 that temporarily seal working chamber 2 during the rotational motion of rotational body 31, 34.

The two sealing portions 32, 33 at one of the rotational bodies 31 (FIG. 1b, 2b) are configured symmetrically to each other and are arranged in pairs at opposite axial ends of rotational body 31 where sealing portions 32, 33 interact in a toothed manner and in the circumferential direction in a form-fitting manner with the complementary contours of rotational body 31 and can be moved axially away from rotational body 31 and towards rotational body 31 while maintaining a continuous seal. Sealing portions 32, 33 are each resiliently preloadable against rotational body 31, 34, where the resilient preload pushes away each of the sealing portions 32, 33 from rotational body 31. As illustrated in FIG. 2a in enlarged detail, sealing portion 32 at its axial sealing surface 32b comprises a line-shaped sealing lip 32d which projects toward working piston 4 and in the circumferential direction extends in a sinusoidal manner. Due to the wave shape, so-called fretting of sealing portion 32 in sealing partner 4 is prevented, because the sealing lip does not always interact with sealing partners 4 at the same place but the point of contact meanders in the radial direction. As a result, wear of sealing portion 32 as well as abrasion at working piston 4 can be reduced. Preferably, all of the sealing portions 32, 33, 35, 36 comprise such sealing lips 32d. Sealing lips 32d are preferably edges 32b that project beyond the respective sealing surface 32b, but are integrally connected to the respective sealing portion 32 and are made of its material.

The two sealing portions 35, 36 (FIGS. 1b, 2b) of the other rotational body 34, however, are configured complementary to each other and disposed in pairs 34 at the opposite axial ends of rotational body 34, where sealing portions 35, 36 interact in a toothed manner and in the circumferential direction in a form-fitting manner and can be moved axially apart from each other and against each other while maintaining a continuous seal. Sealing portions 35, 36 are resiliently preloaded against each other, where the resilient preload forces apart sealing portions 35, 36.

Sealing portions 32, 33, 35, 36 comprise various sealing surfaces 32a/b/c, 33a/b/c, 35a/b/c, 36a/b/c that in the axial direction, in the radial direction and in the circumferential direction face away from respective sealing portion 32, 33, 35, 36. Sealing surfaces 32a, in the radial direction facing away from sealing portion 32, 33, 35, 36, 33a, 35a, 36a, preferably have the shape of a cylindrical jacket portion, whereas sealing surfaces 32b, 33b, 35b, 36b in the axial direction facing away from sealing portion 32, 33, 35, 36 are preferably formed in the shape of circular or annular segments.

In order to seal working chamber 2 in the axial direction, sealing portions 32, 33, 35, 36 are reversibly transferable between a first state in which the respective sealing surface 32b, 33b, 35b, 36b of sealing portion 32, 33, 35, 36 connects flush to or at a distance from an adjacent sealing surface 31b, 34b of rotational body 3, and a second state in which sealing surface 32b, 33b, 35b, 36b further projects in the direction of housing 5 or working piston 4 as a sealing partner beyond sealing surface 31b, 34b of rotational body 31, 34. While maintaining the seal of working chamber 2, each sealing portion 32, 33, 35, 36 is movable only parallel to the rotational axle 30 of rotary piston 3 relative to rotational body 31, 34, 41, whereas all other free degrees of motion of sealing portion 32, 33, 35, 36 are with respect to rotational bodies 31, 34 locked and blocked. The motion of sealing portion 32, 33, 35, 36 relative to rotational body 31, 34 can there, for example, compensate enlarged gaps due to a thermally induced material expansion.

Sealing portions 32, 33, 35, 36 at their—in the direction of rotation—front end comprise bevels 35d, 36d to facilitate penetration of sealing portion 32, 33, 35, 36 in a respective complementary geometry of working piston 4 as a sealing partner during a rolling motion.

Sealing portions 32, 33, 35, 36, 42 are preferably made of heat resistant material, such as ceramics, of ductile material, such as copper, or of porous material, where the material of each sealing portion 32, 33, 35, 36 preferably has the same thermal expansion coefficient as housing 5 and/or working piston 4, so that thermally induced material stresses due to different thermal expansion coefficients can be prevented or at least reduced.

As can be seen in FIG. 3, each rotational body 41 comprises a substantially cylindrical central portion 4a and two circular disk-shaped axial side portions 4b, at the axial end side of which a plurality of movable sealing portions 42 is attached for sealing working chambers 2. Sealing portions 42 are substantially formed identical and circular-segment-shaped, or ring-segment-shaped and arranged in two axially adjacent rows, which are offset in the circumferential direction by approximately half a circumferential length of a sealing portion 42, at the outer circumferential edge of working piston 4. Sealing portions 42 are thereby arranged adjacent in the circumferential direction and overlap in the axial direction, where sealing portions 42 on both axial ends of rotational body 41 form a continuous axial end seal of working chamber 2 closed in the circumferential direction. Sealing portions 42 are movable relative to each other while maintaining the self-contained seal. With these sealing portions 42, auxiliary piston 4 can maintain the seal of working chamber 2 also during rotation about its rotational axle 40.

Two recesses 43 are disposed in succession radially outside the cylindrical center portion 4a and axially within the circular disk-shaped side portions 4b for forming a respective working chamber 2 in the circumferential direction of rotational body 41 and separated by slider 44 (FIG. 3a/b), where slider 44 has a rolling geometry or evolvent geometry adapted to the rolling geometry of the associated auxiliary piston (not shown) to perform a rolling motion in a manner sealing the working piston and the housing. The geometry of rotational body 41 is adjustable, for example, by varying the axial length or by spacing the two axial side portions 4b, respectively, such that the volume of the recesses 43 for forming working chambers 2 can be varied. The geometry of the auxiliary piston is then adapted accordingly.

Rotational body 41 comprises sealing surfaces 41a/b/c which in the axial direction (41b), in the radial direction (41a), and in the circumferential direction (41c) face away from rotational body 41 and which seal working chambers 2 formed in recesses 43 toward the outside during the rotational motion of rotational body 41. This is in particular a seal for working piston 4. The individual sealing portions 42 are during rotation of working piston 4 due to the centrifugal force movable in the radial direction and are with increasing rotational speed increasingly spaced from the rotational axle 40 of working piston 4.

Sealing portions 42 are resiliently preloaded in the direction of rotational body 41, where the resilient preload pulls sealing portions 42 in the direction of rotational body 41, i.e. opposite to the deflection effected by the centrifugal force.

As a result, the increase in the degree of efficiency is accomplished due to specially shaped working pistons 4 with internal recesses 43 for forming working chambers 2, the centrifugal seal by the radially movable sealing portions 42 at rotational body 41 of working piston 4, and the complementarily shaped auxiliary pistons 3 with sealing portions 32, 33, 35, 36 at the rotary bodies 31, 34 movable laterally and in the axial direction. The shape of working piston 4 with working chambers 2 located in the piston volume allows a centrifugal seal with possibly resiliently preloaded sealing portions 42 that seal working piston 4 at both axial ends in the circumferential direction in a self-contained manner against housing 5. An axial seal against housing 5 is thereby no longer required. Several rows of sealing portions 42 offset from each other, due to the larger area as compared to a single row, counteract rapid wear and form a labyrinth seal which lets the working gas escape with more difficulty, even if sealing portions 42 move in the radial direction 42 and gaps thereby arise between sealing portions 42 disposed adjacently in the circumferential direction. Working piston 4 is in no lateral contact with housing 5, whereby no frictional heat is generated. In addition, it can expand without getting seized on housing 5.

Auxiliary pistons 3 extending in the interior are mounted with lateral sealing portions 32, 33, 35, 36, so that there is a lateral seal against working piston 4. These sealing portions 32, 33, 35, 36 can be resiliently mounted and can also use the centrifugal force when a component of motion in the radial direction is possible. Contacting the side wall is effected via sealing portions 32, 33, 35, 36. Rotational bodies 31, 34 of auxiliary piston 3 can accordingly be shaped in a material-saving and light manner.

In an alternative embodiment according to FIG. 4, a respective plurality of movable sealing portions 42 for sealing working chambers 2 is also attached to the outside of the two circular disk-shaped axial side portions 4b of working piston 4. Sealing portions 42 are again formed substantially identical and circular-segment-shaped or ring-segment-shaped but arranged in only one row at the outer circumferential edge of working piston 4. The individual sealing portions 42 are therefore adjacently disposed only in the circumferential direction and not in the axial direction (FIG. 4b/c). The two sealing portions 42 that overlap a slider 44 in the circumferential direction are in the axial direction directly connected to each other by a connecting member 42d, where connecting member 42d interrupts axial side portions 4b of working piston 4 and forms the ridge of slider 44 in the radial direction (FIG. 4a) This connecting member 42d is with the deflection of sealing portions 42 induced by the centrifugal force deflected in the radial direction, where the maximum deflection of sealing portions 42 in the radial direction is restricted by the maximum possible depth of immersion of slide 44 or connecting member 42d, respectively, into the complementary geometry of the sealing partner or auxiliary piston 3, respectively. The deflection of sealing portions 42 connected via the connecting member 42d is thereby automatically regulated, where the maximum deflection can also be transferred to the other sealing sections.

As the detail enlarged in FIG. 4c shows by way of example, sealing portion 42 can at its axial sealing surface 42a comprise a line-shaped sealing lip 42e which extends in the direction of housing 5 and in the circumferential direction in a sinusoidal manner. As a result, fretting of sealing portion 42 in the sealing partner is also for the radially movable centrifugal seal prevented by the wave shape, because the point of contact of sealing lip 42e to housing 5 meanders in the axial direction and therefore does not always pass over the same locations. Consequently, wear of sealing portion 42 and abrasion at housing 5 can be reduced. Preferably all sealing portions 42 comprise such sealing lips 42e, where sealing lips 42e of sealing portions 42 adjacent in the circumferential direction and/or in the axial direction are adapted to each other such that a self-contained wave pattern continuous in the circumferential direction arises. Sealing lips 42e are formed as edges from material of the respective sealing portion 42 and integrally connected thereto so as to project over sealing surface 42a in the direction of sealing partner 5. For improving oil adhesion at sealing surface 42a, a wave-shaped groove can be formed alternatively or in addition to sealing lip 42e which in the latter case can extend in phase or out of phase with sealing lip 42e. FIG. 4e shows a modification of working piston 4 according to FIG. 4d, where the respective sealing portions 42 are themselves formed in a wave-shaped manner and are in the circumferential direction strung together such that a preferably harmonic wave profile arises enclosed about the circumference of working piston 4.

A variant of the rotary piston engine according to the invention is described below with reference to FIGS. 5 to 12 in which a reciprocating piston 71 with counter-cyclical (non-linear) upwardly and downwardly motion is used for recompression of the working gas compressed by working piston 4. Reciprocating piston 71 is located in a control console 7 that is adjustable in housing 5 in the circumferential direction which is described in a similar form in DE 10 2011 109 966. Control console 7 comprises a cylinder with a reciprocating piston 71 oscillating in the cylinder and at the ends of which two ignition chambers 70 are formed, each of which is filled via an ignition chamber inlet 74 and is again emptied via an ignition chamber outlet 74. The working gas contained or generated in ignition chambers 70 is an air-fuel mixture which can be made to explode by self-ignition or externally-supplied ignition, e.g. a respective spark plug 72. In the case of self-ignition, spark plug 72 is not required.

Controlling reciprocating piston 71 is effected by a cam shaft or rotational axle 40 of the working piston with a specially shaped cam 75 with or without a rod connection, or by a pneumatic or a hydraulic lifting system (FIGS. 8a-c). The advantages of the embodiment arise from the fact that, in contrast to only one auxiliary piston 3, all four work cycles are enabled with one revolution and working chamber 2 can be used for flushing ignition chamber 70. Piston 71 can incidentally be used not only as a reciprocating piston 71. It is possible that the working gas is ignited in ignition chamber 70 by reciprocating piston 71 without further compression. In this case, reciprocating piston 71 can also only serve to adjust the volume of ignition chamber 70 across a number of ignition processes.

Characteristic of the rotary piston engine equipped with reciprocating piston 71 is furthermore the reduced gas routing and the high compression ratio which is achieved by the synergetic interaction of the rotary piston system with the reciprocating piston system, where the advantages of both systems are combined in a particularly advantageous manner. It is for further illustration of the method according to the invention convenient to look at the processes and work steps of the two Systems A and B, in which:

• • System A (FIGS. 5a/d, 6a, 7a, 8-12.) denotes the reciprocating piston system comprising ignition chamber 70 with an adjustable cross-section (volume) and a secondary compressor (reciprocating piston 71), and
  • System B (FIGS. 5c/f, 6b, 7b.) denotes the rotary piston system comprising the rotating gas loading unit for pressurizing ignition chamber 70 with working gas in the gas flow direction.

The advantages of the reciprocating piston system, in particular of the camshaft, are to be seen in that

• • ignition chamber 70 can remain closed longer by reciprocating piston 71 than in a continuous up and down motion of a normal crankshaft, so that unintended volume expansion, or having the working gas run back, respectively, is prevented;
  • gas inlets 73 of ignition chamber 70 can be and remain closed so that better control can be obtained;
  • the combustion pressure is effected laterally and does not act upon reciprocating piston 71, where reciprocating piston 71 is supported by the cylinder wall relieving the lifting system and the drive shaft; and
  • a slow or fast motion, for example, for compressing or closing can be enabled by the shape of cam 75.

Cam 75 can be resiliently mounted for the controlled motion in the direction of the axle or be guided via a mechanism. The illustrations are merely to be understood by way of example for illustrating the principle, but alternative reciprocating piston control is also possible.

Cam 75 controls the reciprocating piston 71 preferably such that the gas in the cylinder (or in the ignition chamber 70 of the reciprocating piston compression system) is compressed and then displaced therefrom, where reciprocating piston 71 remains in the top position until full expansion in the working rotary pistons 4 has been achieved.

To optimize combustion performance, the cross-section of the ignition chamber is adjustable preferably manually, for example, by using a screwdriver. The reciprocating piston compression system according to the invention is not restricted to a rotary piston engine. Filling the cylinder can be performed, for instance, by a Wankel engine. The reciprocating piston system can also be used for pre-compression of a working gas for a subsequent thermodynamic process in a rotary piston engine.

Forming the mixture externally (the fuel is admixed outside of ignition chamber 70) may not be useful in rotary piston engines due to complex gas routing. Forming the mixture internally (the fuel is admixed within ignition chamber 70) is therefore preferred.

It is in the reciprocating piston system according to the invention, for example, not necessary to use also an auxiliary rotary piston 3 in addition to the working rotary piston 4 for active compression of the working gas by the rotating components. Working gas can be actively aspired into the ignition chamber alone due to the downward motion of piston 70 and be compressed by the subsequent upward motion of piston 70.

Of particular significance with regard to the seal of working chamber 2 of the rotary piston engine according to the invention is the configuration of working rotary piston 4. Since the working rotary piston according to the invention comprises side parts 4b defining a working chamber 2 in the axial direction of working rotary piston 4 on both sides, only a radial seal of working chamber 2 against housing 5 is still required. Since working chamber 2 is already defined by the axial side parts 4b of working rotary piston 4, a seal against stationary housing components is omitted in these places. For the reason that sealing lips are in this case to have a sealing configuration only in one direction, complex structures can be largely avoided. In addition to less development heat and frictional heat within the rotary piston engine according to the invention, this results in long-term advantages such as reduced wear. Since both the working rotary piston 4 as well as its associated auxiliary rotary piston 3 have substantially the same circumferential speeds, far lower relative speeds occur between the rotating components than between rotating and stationary components.

The method according to the invention for compressing and expanding a working gas being described below with reference to FIGS. 5 to 12 provides that the working gas is compressed by working piston 4 in the first working chamber 2 and is for ignition transferred into the second working chamber or ignition chamber 70, respectively, where the working gas is in the second working chamber or ignition chamber 70, respectively, supplied with fuel and/or further compressed.

Working gas, for example, air is there introduced into the first working chamber 2 in an uncompressed state or already in a compressed state. Compression of the working gas prior to the introduction into the first working chamber 2 can be done, for example, by a turbocharger. The working gas is in the first working chamber 2 compressed by the rotation of working piston 4. Fuel can be injected into the second working chamber or into ignition chamber 70 prior to and/or during and/or after further compression. The working gas is further compressed in the second working chamber or ignition chamber 70, respectively, by reciprocating piston 71, where reciprocating piston 71 can—as previously explained—be driven pneumatically, hydraulically or mechanically. Alternative drive concepts for reciprocating piston 71 are shown schematically in FIGS. 8a to 8c, as well as in FIG. 9. In a pneumatic or hydraulic reciprocating piston drive, the motion of the reciprocating piston can be decoupled from the motion of the rotary piston. When the reciprocating piston, however, is driven mechanically by a cam or an eccentric shaft coupled to the motion of the rotary piston, reciprocating piston 71 and rotary piston 4 preferably run at the same rotational speed. This allows the work cycles in the first and second working chamber 2, 70 to be better coordinated.

FIGS. 5e to 5f schematically illustrate the processes in both Systems A and B, where the following method steps are passed in a total of 4 cycles with two ignitions per revolution:

System B:

• {circle around (1)} aspiration of the working gas through gas inlet 51 into working chamber 2;
• {circle around (2)} precompressing the working gas in working chamber 2 by rotation of working piston 4;
• {circle around (3)} filling ignition chamber 70;

System A:

• {circle around (4)} aspiration of the working gas through ignition chamber inlet 73 into ignition chamber 70 by lowering the reciprocating piston 71 and increasing the volume of ignition chamber 70;
• {circle around (5)} compressing the gas mixture in ignition chamber 70 by an upwardly motion of reciprocating piston 71 and reducing the volume of ignition chamber 70 (mixture formed externally), possibly in combination with injecting fuel into ignition chamber 70 (mixture formed internally);
• {circle around (6)} ignition of the air-fuel mixture (self-ignition or externally-supplied ignition by spark plug 72);
• {circle around (7)} combustion and expansion of the working gas from ignition chamber 70 through ignition chamber outlet into working chamber 2; and
• {circle around (8)} discharging the exhaust gases from working chamber 2;
  System B (when using a turbocharger)
• {circle around (9)} use of exhaust gases by System A

FIGS. 6a and 6b illustrate the working cycles in the reciprocating piston system (System A) and in the rotary piston system (System B). The recompression in System A is effected via a reciprocating piston 71 oscillating in ignition chamber 70, where the mixture is formed internally by fuel injection into ignition chamber 70. With self-ignition of the air-fuel mixture, the mixture is compressed until it reaches the ignition point or fuel is injected into the compressed working gas or an already compressed air-fuel mixture until the ignition point has been reached. Externally-supplied ignition of the air-fuel mixture is effected by spark plug 72.

In System B, gas losses during aspiration of the air due to the leakage through the seals are accepted. The gas loading unit is accordingly designed to aspire and precompress a larger quantity of air. The precompressed quantity of air is used to pressurize the ignition chamber.

The compression pressure can be adjust and influenced in that, for example, in System A, the volume of ignition chamber 70 is changed by reciprocating piston 71 and/or in System B, the volume of working chamber 2 is changed by coaxial displacement of the side parts (4b) of working piston 4 or by replacing working piston 4, in particular when rotational body 41 of working piston 4 is not formed integrally with the axle.

FIGS. 10 to 12 schematically show views to illustrate a chronological sequence of steps of the method according to the invention for compressing and expanding a working gas in the rotary piston engine according to the invention.

The process has the particular advantage that large quantities of air can be aspirated in the working chamber formed by the rotary piston and already be strongly compressed without any reduction in effectiveness due to fuel leakage arising. The fuel can then be supplied to the already compressed working gas in the closed volume of the second working chamber, so that the risk of fuel leakage is reduced. Self-ignition can thus be realized when the working gas is in the second working chamber made to ignite by being supplied fuel and/or by being further compressed. The subsequent compression in the second working chamber ensures thorough mixing of the air-fuel mixture. Alternatively, the air-fuel mixture can be ignited by a spark plug.

In order to increase the degree of efficiency of the rotary piston engine according to the invention, further effective measures can be taken in the area of the lubrication arrangement which is described below with reference to FIGS. 13 to 16.

In an advantageous embodiment according to FIG. 13, lubricant channel 6 is adapted to deliver lubricant S to upper and lower auxiliary pistons 3 and to remove it from there to a lubricant reservoir. Lubricant channel 6, as shown in FIGS. 13a/b/d, there in sections extends around upper (and lower) auxiliary piston 3 and around working chamber 2. Lubricant channel 6 is constructed such that the lubricant S cast off due to the centrifugal force (FIG. 13e) from upper and lower auxiliary piston 3 due to adhesion first adheres to the lubricant channel wall and Is then due to the weight force removed into the collection reservoir (not shown) at the bottom of rotary piston engine 1. Lubricant channel 6 can there in sections run within and in sections outside housing 5.

A collecting portion 60 for collecting lubricant S cast off due to the centrifugal force extends radially outside and axially within upper and lower auxiliary piston 3 in the circumferential direction and opens to the jacket surface of upper and lower auxiliary piston 3. Collecting portion 60, for example, comprises a plurality of parallel grooves 61, each separated by a wall portion 62 and preferably being deeper than wide. Exemplary alternative embodiments of such collecting portions 60 are illustrated in FIG. 13c in cross-section in a plane intersecting rotational axles 30, 40 of rotary pistons 3, 4. A backflow inhibitor can be accomplished by design measures in the collecting portion 60, in particular at upper auxiliary piston 3, and prevent backflow of the previously collected lubricant S from collecting portion 60. For example, wall sections 62 of collecting portion 60 are at their distal end formed having roughly an arrow shape, where the arrowhead faces away from the proximal end. Lubricant S cast off due to the centrifugal force by rotary piston 3 penetrates through the gaps between wall portions 62 into grooves 61 and due to the arrowheads encounters low resistance. Backflow of lubricant S from collecting portion 60 is prevented firstly by the fact that lubricant S due to adhesion adheres to the wall of the lubricant channel, and secondly by the fact that lubricant S clings to the fanned out arrow-shaped ends of wall sections 62 and therefore can not drip back onto auxiliary piston 3 located directly beneath. Lubricant S flows downwardly in lubricant channel 6 along the channel wall due to weight force and is removed in the direction of the collection reservoir and is collected there.

FIG. 13d shows schematic views of the course of lubricant channel 6 and of collecting portion 60 in relation to upper auxiliary piston 3. At an apex 63 of lubricant channel 6, which is preferably located above upper auxiliary piston 3 in a plane enclosing rotational axles 30, 40 of rotary pistons 3, 4, the radius of curvature of lubricant channel 6 can be smaller than the largest radius of upper auxiliary piston 3. Draining lubricant S in lubricant channel 6 in the direction of the collection reservoir can due to this geometry be aided by the influence of weight force. Below apex 63, the radius of curvature of lubricant channel 6, however, is preferably greater than the largest radius of upper auxiliary piston 3. Alternatively, lubricant channel 6 can both at apex 63 as well as also therebelow comprise a larger radius of curvature than the largest radius of the upper auxiliary piston.

FIG. 14a shows a schematic sectional view of a further advantageous embodiment of the rotary piston engine according to the invention perpendicular to the rotational axles of rotary pistons 3, 4 in the intended installation position and FIG. 14b shows rotary piston engine 1 of FIG. 4 in an inclined position in which rotary piston engine 1 is inclined relative to the intended installation position in an axis parallel to the rotational axles by an angle α/2. Backflow of lubricant S received in lubricant channel 6 in particular to upper auxiliary piston 3 is stopped by restricting portions 66 which at least in sections extend in the circumferential direction of upper auxiliary piston 3. Oil collecting areas are provided radially outwardly of border portions 66 that allow tilting and canting of rotary piston engine 1 without the oil flowing back to auxiliary piston 3. Restricting portions 66 and oil guide paths can there be designed such that rotary piston engine 1 can even be operated in a “lying” position when the axles of auxiliary piston 3 and working piston 4 are arranged substantially in a horizontal plane.

In a further advantageous embodiment shown in FIG. 15, lubricant channel 6 comprises several lubricant supply lines 65a running through housing 5 for force-feed circulatory lubrication of mounting points 38 and the axial sealing surfaces of rotary piston 3 with lubricant S. Lubricant supply lines 65a distribute lubricant S across the axial sealing surfaces of rotary piston 3. Lubricant S flowing off the axial sealing surfaces of rotary piston 3 is collected in channel portions 65b extending arc-shaped radially within and axially outside upper auxiliary piston 3 and above mounting points 38 and supplied to mounting points 38 of rotary piston 3. Lubricant S flowing off mounting points 38 of rotary piston 3 is collected in channel portions 65c extending arc-shaped radially within and axially outside upper auxiliary piston 3 and below mounting points 38. Excess lubricant S is discharged directly via lubricant channel 6, into which arc-shaped channel sections 65b, 65c lead via branches 64, into the collection reservoir, is possibly filtered and again supplied via lubricant supply lines 65. This accomplished a self-contained lubricating circuit.

In yet another advantageous embodiment shown in FIG. 16, the lubricant can be delivered from the axial sealing surfaces of rotary piston 3 via upper channel portions 65b directly into lubricant channel 6 without the detour via the mounting points 38 of rotary piston 3. It can thereby be ensured that only unused lubricant reaches mounting points 38 of rotating piston 3. Channel portions 65b, 65c are configured such that lubricant S drains under the influence of weight force from the axial sealing surfaces and mounting points 38 of rotary piston 3 into channel sections 65b, 65c and from there via branchings 64 into lubricant channel 6 and ultimately reaches the collection reservoir. Although the embodiments of the invention have been described individually, the features disclosed within the context of the embodiments of the invention can also be used in combination with each other.

Advantages of the Invention

In summary, the invention discloses various advantageous solutions and embodiments for rotary piston engines 1 and pumps.

In an advantageous embodiment of the invention, the rotary piston engine according to the invention comprises an auxiliary piston 3 with sealing parts or sealing portions 32, 33, 35, 36 for sealing auxiliary piston 3 against working chambers 2 of working piston 4. This embodiment follows the basic principle that two arc-shaped sealing portions 32, 33, 35, 36 mounted laterally o or in rotary body 31, 34 of auxiliary piston 3 are by spring pressure pressed outwardly onto the respective sealing partner or housing 5 or working piston 4, respectively. The jagged shape is to prevent twisting of sealing portions 32, 33, 35, 36 relative to rotating bodies 31, 34 of auxiliary piston 3 and to reduce slippage of the gas. In addition, sealing portions 32, 33, 35, 36 provide for a smaller frictional surface against housing 5 and working piston 4. Lateral sealing portions 32, 33, 35, 36 can additionally be lubricated by force-feed circulatory lubrication.

In a further advantageous embodiment of the invention, the rotary piston engine according to the invention comprises a working piston 4 with sealing points or sealing portions 42 for lateral sealing of working chamber 2 against housing 5. This embodiment is based on the basic principle that arc-shaped sealing portions 42 movably mounted laterally on or in rotary body 41 of working piston 4 are, when working piston 4 rotates, by the centrifugal force being oppositely to a resilient preload pressed radially outwardly onto housing 5 or auxiliary piston 3. The jagged shape of sealing portions 42, 41, is again to prevent twisting relative to rotary body 41 of working piston 4 and to reduce slippage of the gas. When sealing portions 42 are arranged overlapping in several rows, the gaps in the spaces arising during radial deflection of sealing portions 42 can be covered and closed by overlapping sealing portions 42, so that even less pressure losses arise.

In a further advantageous embodiment of the invention, sealing portions 32, 33, 35, 36, 42 are preferably made of materials offering less wear or better gliding properties than the respective rotary pistons 3, 4, for example, copper, ceramics, etc. Sealing portions 32, 33, 35, 36, 42 are preferably mounted or formed only at the outer edge of rotational bodies 31, 34, 41 in order to better seal working chambers 2. Alternatively or additionally, sealing portions 32, 33, 35, 36, 42 can also cover a jacket surface and/or at least one axial end side of rotational bodies 31, 34, 41 so that, for example, a kind of heat shield against working chamber 2 is formed. In this case, ceramics are suitable material. Another option is to bevel the—in the direction of rotation—front ends of sealing portions 32, 33, 35, 36, 42, i.e. where for instance the male and female rolling geometries of auxiliary piston 3 and of working piston 4 meet, so that male rotary piston 3, 4 does not impact the edge of female rotary piston 3, 4 when material expands. This results in the advantage of a better seal against the side walls of working chambers 2 also when material expands. Sealing portions 32, 33, 35, 36, 42 can also be replaced in an easier and more inexpensive manner than rotary pistons 3, 4. Rotary pistons 3, 4 can be configured narrower and be more flexibly adapted to certain conditions supplementing sealing portions 32, 33, 35, 36, 42.

In yet another advantageous embodiment of the invention, housing 5 of the rotary piston engine according to the invention is designed not only for receiving rotary pistons 3, 4, but in particular also for collecting and draining lubricants S from rotary pistons 3, 4 into a collection groove or an oil pan. The invention there makes use of the centrifugal force of rotating rotary pistons 3, 4 in order to cast off and collect lubricants exiting on rotary piston, 3, 4, for example, oil of the force-feed circulatory lubrication, and to drain them via lubricant channel 6 in the housing behind working piston 4, at least in sections around working piston 4, or via drain lines outside housing 5 into the oil pan. A collecting portion 60 provided with collecting grooves 61 or slits there collects oil running or dripping down in housing 5 in the area of auxiliary piston 3 and delivers it via lubricant channel 6 to the oil pan. Working piston 4 is thereby less contaminated with oil residues and working chambers 2 are in the compression and expansion stage protected from flooding with oil (cf. oil pressure surge with reciprocating pistons). In particular with the force-feed circulatory lubrication provided, higher pressures and larger quantities of oil are possible allowing for more consistent and reliable lubrication at high rotational speeds.

Collecting portion 60 with the oil collecting grooves 61 in the circular arc area of the housing portion for receiving auxiliary piston 3 facilitates adhesion of the oil by adhesion force and drains the oil sprayed onto the housing wall in a controlled manner along the housing wall into the collection reservoir. An efficient oil drainage system is thereby accomplished. Collection strips and/or depressions in the lateral region of auxiliary piston 3 disposed above working piston 4 drain oil running or dripping down (e.g. of the sliding bearing) and forward it into the collection reservoir. Working piston 4 is also thereby less contaminated with oil residues and working chambers 2 are in the compression and expansion stage protected from flooding with oil. Excess oil is in a reciprocating piston engine the cause for so-called oil pressure surge and for bad combustion. Higher pressures and larger quantities of oil are possible with force-feed circulatory lubrication allowing for more consistent and reliable lubrication at high rotational speeds. Since auxiliary piston 3 does not contact housing 5 disposed above, no lubrication is required. This results in fewer problems with friction, thermal expansion and fit. Lubricant channel 6 is adapted to drain dripping oil in the resting state as well as in the operating state in a controlled manner and to create a larger collection area for the oil that is cast off.

Further preferred embodiments of the invention arise from any combination of the features described in the embodiments.

All embodiments and features disclosed herein can be combined with one another. The teaching of the invention is applicable in particular regardless of the shape and number of working and auxiliary pistons.

LIST OF REFERENCE NUMERALS

• 1 rotary piston engine
• 2 working chamber
• 3 auxiliary piston
• 4 working piston
• 5 housing
• 6 lubricant channel
• 7 control console
• 30 rotational axle—auxiliary piston
• 31, 34 rotational body—auxiliary piston
• 31a, 34a axial sealing surfaces—auxiliary piston
• 31b, 34b radial sealing surfaces—auxiliary piston
• 31c, 34c sealing surfaces in the circumferential direction—auxiliary piston
• 32, 33 sealing portions—auxiliary piston
• 32a, 33a radial sealing surfaces—sealing portion auxiliary piston
• 32b, 33b axial sealing surfaces—sealing portion auxiliary piston
• 32c, 33c sealing surfaces in the circumferential direction—sealing portion auxiliary piston
• 32d sealing lip—sealing portion auxiliary piston
• 35, 36 sealing portions—auxiliary piston
• 35a, 36a radial sealing surfaces—sealing portion auxiliary piston
• 35b, 36b axial sealing surfaces—sealing portion auxiliary piston
• 35c, 36c sealing surfaces in the circumferential direction—sealing portion auxiliary piston
• 35d, 36d bevels—sealing portion auxiliary piston
• 37 cavity—auxiliary piston
• 40 rotational axle—working piston
• 41 rotational body—working piston
• 41a radial sealing surfaces—working piston
• 41b axial sealing surfaces—working piston
• 41c sealing surfaces in then circumferential direction—working piston
• 42 sealing portions—working piston
• 42a radial sealing surfaces—sealing portion working piston
• 42b axial sealing surfaces—sealing portion working piston
• 42c sealing surfaces in the circumferential direction—sealing portion working piston
• 42d connecting portion—sealing portion working piston
• 42e sealing lip—sealing portion working piston
• 43 recess—working piston
• 44 slider—working piston
• 51 gas inlet—housing
• 52 gas outlet—housing
• 60 collecting portion—lubricant channel
• 61 groove—lubricant channel
• 62 wall portions—lubricant channel
• 63 apex—lubricant channel
• 64 branching—lubricant channel
• 65 lubricant supply line—lubricant channel
• 65a channel portions—lubricant channel
• 65b channel portions—lubricant channel
• 65c channel portions—lubricant channel
• 66 restricting portion—lubricant channel
• 70 ignition chamber
• 71 reciprocating piston or adjustable piston
• 72 spark plug or injector
• 73 inlet ignition chamber
• 74 outlet ignition chamber
• 75 eccentric/cam

Claims

1-10. (canceled)

11. A rotary piston engine for compressing and/or expanding a working gas in at least one working chamber comprising at least one rotary piston with at least one rotatably mounted rotational body and at least one sealing portion that can be moved relative to the at least one rotational body for sealing the at least one working chamber, wherein at least two sealing portions together form a continuous seal and are movable relative to each other while maintaining a continuous seal.

12. The rotary piston engine according to claim 11 wherein the at least one rotary piston comprises at least one recess for forming the at least one working chamber.

13. The rotary piston engine according to claim 11 wherein the at least one sealing portion is configured such that, during rotation of the at least one rotary piston, the at least one sealing portion is movable due to the centrifugal force, and wherein the at least one sealing portion is due to the centrifugal force spaced from a rotational axle of the at least one rotary piston.

14. The rotary piston engine according to claim 11 wherein at least two sealing portions are in an axial direction and/or in a radial direction and/or in a circumferential direction disposed adjacent and/or overlap each other.

15. The rotary piston engine according to claim 11 wherein at least two sealing portions together form an enclosed or self-contained seal.

16. The rotary piston engine according to claim 11 wherein at least two sealing portions are movable relative to each other while maintaining a closed or self-contained seal.

17. The rotary piston engine according to claim 11 wherein at least two sealing portions are identical or symmetrical or complementary to each other.

18. The rotary piston engine according to claim 11 wherein at least two sealing portions seal the at least one working chamber completely in an axial direction and/or in a radial direction and/or in a circumferential direction.

19. The rotary piston engine according to claim 11 wherein at least two sealing portions are arranged in pairs at opposite axial ends of the at least one rotational body.

20. The rotary piston engine according to claim 11 wherein at least two sealing portions are resiliently preloaded or preloadable against each other, and wherein the resilient preload is configured to push apart or press together the sealing portions.

21. A method for compressing and/or expanding a working gas in a rotary piston engine, the method comprising:

compressing the working gas by a rotary piston in a first working chamber; and

transferring the working gas into a second working chamber in order to be ignited;

wherein the working gas is in the second working chamber supplied with fuel and/or is further compressed.

22. The method according to claim 21, wherein the method comprises at least one of the following:

a) the compressed working gas is passed through the rotary piston and/or through a housing of the rotary piston engine;

b) the fuel is injected into the second working chamber prior to and/or during and/or after the further compression;

c) the working gas is in the second working chamber further compressed by at least one reciprocating piston, wherein the reciprocating piston is driven pneumatically and/or hydraulically and/or mechanically by a cam or eccentric shaft coupled to the rotary piston motion, wherein the at least one reciprocating piston and the rotary piston run at the same rotational speed;

d) the working gas is introduced already in a compressed state into the first working chamber, wherein the compression is effected by a turbocharger;

e) the working gas is in the second working chamber made to ignite by being supplied with fuel and/or by further compression;

f) the ignited working gas is passed through the rotary piston and/or through the housing of the rotary piston engine, radially outwardly from the second working chamber into the first working chamber.